finite

       - BSD floating-point classification functions

SYNOPSIS
       #include <math.h>

       int finite(double x);
       int finitef(float x);
       int finitel(long double x);

       int isinf(double x);
       int isinff(float x);
       int isinfl(long double x);

       int isnan(double x);
       int isnanf(float x);
       int isnanl(long double x);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       finite(), finitef(), finitel():
           _BSD_SOURCE || _SVID_SOURCE
       isinf():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
           _ISOC99_SOURCE;
           or cc -std=c99
       isinff(), isinfl():
           _BSD_SOURCE || _SVID_SOURCE
       isnan():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE;
           or cc -std=c99
       isnanf(), isnanl():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600

DESCRIPTION
       The  finite() functions return a nonzero value if x is neither infinite
       nor a "not-a-number" (NaN) value, and 0 otherwise.

       The isnan() functions return a nonzero value if x is a NaN value, and 0
       otherwise.

       The  isinf()  functions  return 1 if x is positive infinity, -1 if x is
       negative infinity, and 0 otherwise.

NOTES
       Note that these functions are obsolete.  C99 defines macros isfinite(),
       isinf(), and isnan() (for all types) replacing them.  Further note that
       the C99 isinf() has weaker guarantees on the return value.  See fpclas-
       sify(3).

SEE ALSO
       fpclassify(3)

COLOPHON
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